Nuclear Stress Test

Nuclear Stress Test with Exercise

The purpose of an exercise cardiac nuclear stress test is to evaluate the blood flow to the heart muscle when the heart is under stress (exercise) and at rest. Before exercise, a small intravenous (IV) line will be started in a vein in your arm or hand. The IV will allow us to inject the Cardiolite marker into the bloodstream at the appropriate time.

What will happen during the test?

During a nuclear stress test, first you will be injected with Cardiolite, a radioactive tracer, in the vein of your arm or hand. Cardiolite is taken up by the heart muscle through the coronary arteries in proportion to the blood flow to it. This material should not affect you in any way.  It is then necessary that you wait between 20 and 45 minutes for the tracer to circulate to the heart. You will be instructed where to wait and given water at this time. You will then be placed on a special chair (similar to a dental chair) and a Nuclear SPECT (single-photon emission computerized tomography) camera will travel across your chest to obtain the rest images of your heart. This takes approximately 15 minutes. It is necessary that your arms be placed above your head during the cardiac stress test.

Next, you will be moved to a stress room to continue your study. Electrodes will be placed on your chest, similar to an electrocardiogram (EKG). Your blood pressure, heart rate, and EKG will be monitored and recorded by an attending nurse.

You will be asked to perform a "graded" exercise test on a motor-driven treadmill. The first stage will begin with the treadmill at a slow speed and a slight uphill inclination. Every three minutes the treadmill will increase in speed and elevation.  The nurse may stop the test at any time for medical reasons or you may stop the test because of significant fatigue or discomfort. In general, however, we encourage you to exercise as long as possible in order to maximally stress the blood flow to your heart.

About 90 seconds before you need to stop exercising, a small amount of the radioactive Cardiolite will be injected into your bloodstream through the IV line and allowed to circulate during the final minute of exercise. The nurse will monitor your heart rate, blood pressure, and EKG for several minutes following the exercise.

You will then be instructed as to when a second set of images will be made of your heart. This can range anywhere from 15 minutes post-exercise to 3 hours post-exercise, depending on the schedule. When you return, a second set of images will be made in the same way as the first set of images and will also take approximately 15 minutes. 

When both sets of images are completed, the Upstate Cardiology physician will have a view of your heart at both rest and stress. Even though it may be hours after exercise for your "stress" images, the isotope entered your heart at maximum stress and will remain there until images are completed.

Nuclear Stress Test without Exercise

The purpose of a non-exercise cardiac nuclear stress test is to assess the blood flow to the heart muscle at peak stress and again at rest. This test is used for patients who are unable to exercise on a treadmill. The medication Lexiscan is given, which acts to dilate the coronary arteries. 

What will happen during the test?

For a non-exercise nuclear stress test, first you will be injected with Cardiolite, a radioactive tracer, into the vein of your arm or hand. Cardiolite is taken up by the heart muscle through the coronary arteries in proportion to the blood flow to it. This material should not affect you in any way. It is then necessary that you wait between 20 and 45 minutes for the tracer to circulate to the heart. You will be instructed where to wait and  given water at this time. You will then be placed on a special chair (similar to a dental chair) and a Nuclear SPECT (single-photon emission computerized tomography) camera will travel across your chest to obtain the rest images of your heart. This process takes approximately 15 minutes. It is necessary that your arms be placed above your head during this time.

Next, you will be moved to a stress room to continue your study.  Electrodes will be placed on your chest in the same manner as for an electrocardiogram (EKG). Your blood pressure, heart rate, and EKG will be monitored and recorded by an attending nurse.

A small intravenous (IV) line will be started in a vein in your arm. The IV will allow us to inject the Lexiscan and Cardiolite into the bloodstream at the appropriate time. Lexiscan will be administered by the technologist over approximately 30 seconds while you are monitored by both a nurse and EKG technician. Immediately following the Lexiscan, a small amount of Cardiolite will then be injected through the IV. After several minutes of monitoring, the IV will be removed as well as most of the EKG electrodes.

You will then be instructed as to when a second set of images will be made of your heart. This can range anywhere from 45 minutes post Lexiscan to 3 hours post Lexiscan depending on the schedule. When you return, a second set of images will be made in the same way as the first images and will also take approximately 15 minutes. 

When both sets of images are completed, the Upstate Cardiology physician will have a view of your heart at both rest and stress. Even though it may be hours after Lexiscan for your "stress" images, the isotope entered your heart at maximum stress and will remain there until images are completed.

Frequently Asked Questions

What is the preparation for the test?

  • Do not eat or drink anything past midnight the day before your test.
  • It is very important that you do not have any food, beverages, or medications that contain caffeine 24 hours before the test. Remember, this includes chocolate.
  • Wear loose, comfortable clothing and comfortable walking shoes. Do not wear boots, jumpsuits, overalls, or a dress.
  • You should continue to take all medications (up to midnight the night before the test), unless your cardiologist instructs you otherwise.

What should I bring with me to the test?

  • Inhalers, if you use them
  • All medications in their original bottles
  • Insurance card
  • Referral for Cardiolite Stress test if required by your insurance company

Once your appointment has been scheduled, it is very important that you notify us if you are unable to keep your appointment. Please notify our office at least 24 hours in advance if you are unable to keep your appointment. We would appreciate this notification due to our tight scheduling restrictions. Thank you for your cooperation.

What is the accuracy of this test?

In general, the diagnostic accuracy of the standard cardiac EKG stress test is about 68% and may therefore provide limited information. This accuracy  

is further diminished in some patients because of certain medications, abnormalities on the resting EKG, etc. The more sensitive Cardiolite nuclear stress test is very useful in these instances and provides what we call a physiologic assessment of blood flow. In addition, the Cardiolite test provides very useful information about your risk of having a heart attack. Although no test will always provide 100% accurate information, the presence or absence of a significant blood flow problem to the heart muscle can usually be documented with this test.

Who will give me the test results?

If your test was ordered by a provider who is not an Upstate Cardiology physician, you will receive your test results from the provider who ordered your test. If there is a critical finding on your test, Upstate Cardiology will notify you within 24 hours of your test and will also make sure the ordering provider is aware. Otherwise, if you have not heard from your provider and it has been two weeks since your test, we recommend that you call the provider who ordered the test to seek results.

If an Upstate Cardiology physician ordered your test, you will receive and review your test results with your cardiologist at a follow up visit scheduled for that purpose, unless your cardiologist indicated that he or she will call you with your results. If your diagnostic test reveals a critical finding, we will call you within 24 hours of your test to expedite your care and follow-up. If you've not heard from or seen us within 2 weeks of your test, please call 864-235-7665.